| 摘要 |
PROBLEM TO BE SOLVED: To provide a dielectric filter miniaturized to allow lead wires bonded to a dielectric coaxial resonator to be shortened and the area of a mounting board to be reduced. SOLUTION: The dielectric coaxial resonator 10 has a stepped impedance type structure having two different characteristic impedances connected in series, using a dielectric ceramic block 11 having a columnar body deformed from its middle. The ceramic block 11 has a substantially circular through-hole 14 in a sectional view along the axial line of the columnar body. The columnar body is a composite of a first square column 15 or a first circular column 19 with a second square column 16 or a second circular column 18 having a smaller outer diameter than that of the first column 15 or 19 and takes the end face of the second column 16, 18 as an open end face 17, and electrodes 12, 13a, 13b, 13c, 13d are provided on all the surfaces but the open end face 17.
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